Tobacco smoke filtering material



United States Patent TOBACCO SMOKE FILTERING MATERIAL Richard G. Taylor, Olathe, Kans.

No Drawing. Application March 21, 1955 Serial No. 495,825

1 Claim. (Cl. 131-208) This invention relates to improvements in tobacco smoke filters.

The use of filters to remove noxious gases and entrained deleterious substances originating from tobacco smoke and from the combustion of cigarette paper is well known, as is the treatment offiltering material with different types of chemicals to abstract objectionable alkaloids, nicotines and other harmful ingredients from tobacco smoke. The success of such filters whether chemically treated or not has been questionable since such harmful constituents of the smoke as have been removed are exceedingly small, being taken out principally by mechanical filtration or by absorption into the filter mass.

The instant invention seeks to alter the characteristics of a cellulosic filtering material by treatment with selected' chemicals which will have the possible effect of changing the pH of the colloidal smoke to coagulate, separate and cause deposition of the harmful ingredients therefrom while simultaneously providing and offering an adsorbent agent to interrupt and accumulate the separated deleterious matter, preventing all but very small amounts of the noxious substances to pass.

Smoke originating from the combustion or partial combustion of tobacco in a cigarette, pipe or cigar is colloidal in nature and is actually a mixture of different types or classes of colloids, such as a liquid in gas, a solid in gas or the combination of two gases. Since there are many elements of a distillation process involved in burning tobacco slowly as is done in smoking, various entrainment processes are also involved; thus the complexity of the colloidal systems set up is greatly increased. If to these complex colloidal systems is added the colloidal systems set up by the burning of cigarette paper, the complexity of the resultant smoke is to that extent likewise increased. It should be apparent that the chemical composition of the cigarette paper being much different from that of the burning tobacco, different chemical substances will be introduced to the tobacco smoke from the burning paper and different chemical substances will occur and be blended with the colloidal systems of the volatilized constituents of the tobacco.

It is generally known that various procedures and devices of both chemical and physical nature are used to coagulate colloids thereby causing the dispersed phase to settle out. As an example, devices such as the Cottrell smoke eliminator breaks smoke colloids by allowing the smoke to pass through the discharge of an electric arc. Changing the pH of the dispersion medium likewise will cause many colloidal systems to break down. Adding certain electrolytes to an emulsion thereby introducing chemical ions may cause the coagulation of colloidal systems. The rate and magnitude of such coagulation is de-.

terminable and follows the Hoifmeister series.

Among the chemical substances which occur in tobacco smoke are nicotine, malic acid, citric acid, oxalic acid, malonic acid, tannin, carbon monoxide, carbon dioxide and certain metallic oxides. Tars and other chemical substances originating from burning paper include carbon monoxide, carbon dioxide, methane, ethylene, wood tar, acetic acid, formic acid, acetone, phenols and the fused and saturated ring systems. The contaminants included in the smoke of burning tobacco and paper are tannins, phenols, volatile and entrained organic acid, fused and saturated ring systems, entrained alkaloids, volatile and sublimated metallic oxides, volatile and entrained organic bases fromtobacco and cigarette paper, volatile and entrained tarry materials from tobacco and cigarette paper smoke.

It is general information that the dispersed phase of colloidal systems may be adsorbed, absorbed or occluded by a great variety of materials. One prerequisite of such phenomena is that the adsorbing agent expose a large surface area to the dispersed phase or that the adsorbing agent be porous, thereby making provision for capillary adsorption. If such adsorbing or occluding agent be in intimate contact with the dispersed phase .at the time of coagulation, adsorption from the colloidal system will be greatly facilitated. Cellulose, wood fiber and other natural and synthetic fibrous material are capable of reacting with monohydric, dihydric, trihydric, and polyhydric bases. Likewise, monobasic, dibasic, tribasic and polybasic acids have been used, all with variable degrees of successful results. Members of the sodium family seem to exert a similar effect upon cotton or other types of cellulosic materials. Lithium, sodium and potassium combine with the cellulose in about the same proportion, but cellulose reacts less with cesium and rubidium. In all cases dilute solutions of this family of hydroxides result in swelling of the cellulose. Cellulose appears to react less readily with the metals of group II and group III, but there will be greater tendency to form association complexes with accompanying swelling.

Treating cellulose with acids or bases brings about some hydrolysis, thereby increasing the movement of particles in the micelle or fibril of the cellulose fibers. The. reaction of a cellulose with strong mineral acids approximates that occurring with strong mineral bases. Strong organic bases such as quaternary ammonium bases, trialkyl sulfonium bases and guanidinium bases will react 1 with cellulose; also acid anhydrides and acid chlorides form esters with cellulose.

Cellulosic materials are composed of chain molecules arranged parallel to each other in bundles and held in position by hydrogen bonds between opposing hydroxyl groups. These bundles are known as micelles which in turn are built up to form the fibrils. sumed that the cellulose is made up of glucose anhydride or lactone rings or glucopyranose rings attached in the chain at the 1 and 4 positions. Thus free hydroxyl or alcoholic groups will occur in the 2, 3 and 6 positions. The alcohol group in the 6 position is a primary alcohol .and the 2 and 3 positions are occupied by secondary alcoholic groups. This is true for all the pyranose groups other than at the end of the chain, and this latter group has four free hydroxyl groups. If the assumption is made that about half the hydroxyl groups of the cellulose system are surface hydroxyls and about half of the hydroxyls are wrapped up in the micelle, it is readily conceivable that the surface hydroxyls will react with the chemical substances first. These hydroxyl groups react with many of the chemical substances with which some alcohols are known to react. They will react with basic material to form alcoholate-like compounds or they may react to form association complexes. Metallic sodium in liquid ammonia reacts with cellulose with liberation of hydrogen to form sodium cellulosate. Also, an 18% solution of sodium hydroxide at 20 C. exerts a mercerizing effect upon cotton. Lower concentration of sodium hydroxide may react chemically or may tend to form association complexes perhaps depending on the temperature to which Patented Dec. 31, 1957.

Basically it is asstirred until wet and then compressed beneath the surface of the solution. The beaker is placed in a wateribath, the temperature in the beaker brought to 90 (3-. and maintained at that temperature for 20 minutes. As-much liquid as possible is decanted and the cotton is then washed with 4O'0 ml; distilled water. The precise; is squeezed nary as possible or een't'rifuged if one is available. The cotton is washed ina similar my three additional t'irnes. The" treated cotton i's'the n flu'fldupwell and driedin a spin dryer at 75 C.

EXAMPLE N O. II

15 grains of cotton is treated inexactly the emanatine'rfothe'r than that 200" ml. of distilledwater to which 4 grams of calciumoxide-is added ass-alerted to'fs'lak'e. Five gr'arns" 6f sodium-chloride is addedto thiss'olt'ition'.

EXAMeLE NO. 1m

15 grants of cotton is treated in exactly the same manher other than 200 'ml.- of 3% aluminum acetates'olutioncontaining 5' grams ofsodium' chloride is used; I

The fiodiuin chloride tfie'd in thispl'ocduk seems to increase the swelliri'g "of the co't'to'n fiber. A use c'entag'e 'of salt-is adsereed=a e1ndea orhld by the cellulose as asoeiation eonipleires This elemcieases the eiejetrelyte cem nt at the materia1,-- therein-increasing the coagulating effect of the treated cellulose.

resists determine the ec'ia gnlatin'g' efict'of the materials made according-tortheprooedures described in the examples above gave the following'r'es'ults:

Test made an "Example N0. 1 material 20 cigarettes were smoked in .atcst machine using the material produced in Example No. I above; the amount of filtering material employed being comparable to that used in a conventional filtertip cigarette. The smokewas drawn through the filter at about the average rate as smoking and trapped in a solvent consisting of ethyl alcohol; beniene and water. Each cigarettewasallowed to burn down leaving a stub of about the usual length left by smokers. The solvent was evaporatedslowly over a water bath and the residue weighed. The 20 filters from the cigarettes which had been smoked were extracted with a comparable amount of the same solvent as was used in the trap. The solvent was evaporated in the same way and the residue weighed. Repeated runs on 20 cigarettes of the same brand showed that approximately 5% as much tarry residue went through thefiiters as was retained by the filter.

Test made an Example N0. II material The procedure followedin this test was the same as that made in Test No. I, above. The material used was that produced by Example No. III and 8% as much tarry residue went through the filter as was retained by the filter.

From the foregoing it will be seen that there has been provided an improved type "of tobacco smoke treating material whereby materials are removed and collected upon the smoke treating material, the mass of said material providing a large surface.

It will be seen that this invention is one well adapted to attain all of the ends and objects hereinabove set forth together withother advantages v'vhieh are obvious and which are inherent to the procedure.

It will be understood that certain features and subcornbinat ions are of utility and may be employed without reference to other features and subcombinations. This is contemplated by'land is within the scope of the claim.

As many possible embodiments maybe made of the invention without departing'frorn the scope thereof, it is :0 be' understood that all matter herein set faith is to be interpreted as illustrative and not in a limiting sense.

Having t usaesmew my invention, I claim:

A "dried, fiiiffd, adsorbent cellulo sic material treated with a dilute solution of a basic substance and sodium chloride, said material adapted for use as a filtering material to remove volatilized and entrained "substances from tobacco smoke.

R'e'feren'es 'Cited in the 'file of this patent UNITED STATES PATENTS 

